PPT Slide
In the picture on the left, he has extra wires (red lines).On the right only one wire was used to pull the main ones apart. This device works very well. By using a valve you can control the film speed and thickness. The thickness is very uniform and allows for very accurate measurements. The film can move downward at about 3 meters per second, (depending on the size of setup) meaning that the film is never in contact with air for more than a second.